Combination of Activated Carbon with Biological Wastewater Treatment at Full-Scale - Activated Carbon for Water and Wastewater Treatment - page 132

5.1.1.6
Treatment of Pharmaceutical Wastewaters
As shown in Chapter 3, the PACT system can also be operated in the sequencing
batch reactor (SBR) mode. Synthetech, Inc. in Albany, Oregon made use of the
SBR-PACT system for the treatment of a pharmaceutical chemicals production
effluent [13]. The company produced peptide building blocks and specialty
amino acids, alcohols, esters, amides, and chiral intermediates that are distri-
buted to pharmaceutical companies. A wide range of chemicals were used in the
synthesis of these products. This resulted in large fluctuations in the type and
concentration of contaminants in the wastewater. The wastewater was finally
discharged to the Publicly Owned Treatment Works (POTW) of the City of Albany.
In 2001, the Albany POTW became subject to Federal Pharmaceutical Pretreat-
ment Standards imposed by the USEPA. These treatment standards include
limitations for 23 VOCs, pH, and ammonia. The POTW also levies a toll charge on
industrial wastewater dischargers tied to BOD and total suspended solids (TSS)
loadings.
In bench-scale testing in biological reactors, an equal mixture of process wastes
(COD: 30 000-90 000mg L 1 ) and non-process wastewaters (COD: 1000-2000mg
L 1 ) was used as a feed. In such cases, VOCs were removed without a problem.
Also, efficient BOD and COD removal was observed. Some fraction of ammonia
was removed by assimilation into biomass. However, the removal of ammonia via
nitrification was problematic because of the inhibitory effect of sulfate [13].
Using the results of the bench-scale testing program, the company decided on
full-scale application of PACT in order to meet the standards and decrease the costs
of discharge. The treatment system consisted of an evaporator to pretreat the pro-
cess stream and a PACT unit to further treat the evaporator distillate after com-
bining it with the non-process wastewater (Figure 5.3). Evaporation was chosen as a
pretreatment step to eliminate total dissolved solids (TDS) and to control ammonia.
The evaporator is a factory-built system that exploits the combined effect of vacuum
and heat pump technology to carry out distillation at low temperatures. The PACT
system is a factory-built SBR unit consisting of aeration/settling tank, aeration
blower, air distribution system, and delivery systems. The SBR-PACT system
was designed to handle approximately 13.25 m 3 d 1 of non-process water and
13.25 m 3 d 1 of evaporator condensate from the process water [13].
For the system shown in Figure 5.3, effluent COD was 261mg L 1 with a
removal efficiency of 98%. The effluent BOD to the sewer averaged about
0.9 kg d 1 or 44mg L 1 . Thus, these values met the target BOD of Albany City,
specified as 88.5 kg d 1 . Prior to the installation of the PACT system, effluent
discharges frequently surpassed 450 kg d 1 , which necessitated that the process
wastewater be treated offsite. However, after the installation of the PACT system
no wastewater had to be treated offsite. Moreover, VOCs were consistently
eliminated, and their levels easily complied with Federal Pretreatment Standards.
The wastewater was rich in nitrogenous compounds such as amino acids. In the
PACT system, nitrification and denitrification were also achieved by switching
aeration on and off during the SBR cycle [13].